Removable grounding receptacle for panelboards



Feb. 23, 1965 G. H. FARNSWORTH REIOVABLE GROUNDING 'RECEPTACLE FORPANELBOARDS Filed June 27. 1960 4 ShoetNhapt 1 Feb. 23, 1965 G. H.FARNswoRTH 3,170,744

REMOVABLE caounomc; REcEPmmE 1m mammals Filed June 27, 11960 4Sheets-Sheet 2 K) 0: {CD 0.0 (5H W fi L Feb. 23, 1965 REMOVABLEGROUNDING RECBPTACLE FOR PANELBOARDS Filed June 27. 1960 G. H.FARNSWORTH 4 Sheets-Sheet 4 210/ U m .70. A70 V 0 y C1 /3 k/J /4INVENTOR. 25 550m 11 mower/l United States Patent 3,170,744 REMOVABLEGROUN DING RECEPTACLE FOR PANELBOARDS George H. Farnsworth, GrossePointe Woods, Mich.,

assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., acorporation of Pennsylvania Filed June 27, 1960, Ser. No. 38,904 Claims.(Cl. 339-14) This invention relates to electrical receptacles forreceiving plug caps and more particularly to a receptacle of this typewhich is constructed to be mounted in a panelboard in the locationnormally occupied by a circuit breaker.

Heretofore, it has been the practice to provide electrical outlets byrunning conductors through conduits extending from panelboards to outletboxes having electrical plug-in receptacles. This requires aconsiderable expenditure of time and material. Another common practiceof providing convenience receptacles is to install them directly on thefront cover of a panel. Considerable work is required since the covermust be specially drilled, refinished and the receptacles installed onthe cover. In addition, it is diflicult to add more receptacles if suchis required.

The instant invention provides a plug-in receptacle which isconveniently mounted in a residential lighting panel especially of thetype utilized in basements. Most residential basements are not providedwith any wall mounted receptacles. Therefore, in order to plug in anelectrical tool for use in the basement, it is necessary to first removea bulb from a ceiling lamp holder and replace the bulb with a screw typeplug receptacle.

The residential panels of most newer buildings are provided with anumber of circuit breaker locations which are not occupied by circuitbreakers. It is at one of these unoccupied circuit breaker locationsthat the receptacle of the instant invention is intended to be installedso that a permanent electrical outlet is always available.

The panel receptacle is preferably a three-wire device. That is, adevice having three prong-receiving contacts, two of which are connectedto the source of electrical energy and the third of which is connectedto equipment ground. The equipment grounding contact is provided with alocking car which is moved into locking position when the equipmentgrounding contact is deflected upon engagement by a plug prong. When thelocking ear is in locking position it cooperates with a formation on thepanelboard rib to which the receptacle is mounted in a manner to preventdismounting of the receptacle. That is, the receptacle cannot bedismounted from the panelboard while a plug cap is mounted on thereceptacle.

The other two contacts of the receptacle are of novel identicalconstruction and each includes three blades extending in the samedirection. The faces of two of the blades are in opposing relationshipto receive a plug prong therebetween while the third blade is orientedat right angles to the other blades so that the face of the third bladeopposes the edges of the other two blades and is operatively positionedto receive a plug prong oriented at right angles to the plug prong whichwould be engaged by the first two recited blades. With this arrangement,through a slight modification of the receptacle housing, the receptacleis constructed to receive either parallel prongs for connection to a 120volt circuit or aligned prongs for connection to a 240 volt circuit.

Accordingly, a primary object of the instant invention is to provide anovel receptacle adapted to be mounted at a circuit breaker location inapanelboard.

Another object is to provide a novel receptacle construc-tion includingmeans for locking the receptacle in 3,170,744 Patented Feb. 23, 1965 thepanelboard to prevent dismounting therefrom when a plug is inserted inthe receptacle.

Still another object is to provide a novel receptacle contact meanswhich is constructed to accept fiat-type plug prongs oriented parallelto one another or in alignment with one another.

Still another object is to provide a novel receptacle constructionwherein the contacts connected to the power source are identical inconstruction and positioned to receive flat plug prongs orientedparallel to each other or in alignment with one another.

These as well as other objects of the instant invention shall becomereadily apparent after reading the following description of theaccompanying drawings in which:

FIGURE 1 is an exploded perspective View illustrating the manner inwhich the receptacle of the instant invention is mountable on apanelboard FIGURE 2 is a fragmentary plan view of a panelboard includingcircuit breaker means and a pair of receptacles constructed inaccordance with the teachings of the instant invention.

FIGURE 3 is an end view of the panelboard illustrated in FIGURE 2looking in the direction of arrows 33 of FIGURE 2.

FIGURE 4 is a side elevation of a receptacle mounted to a rib with therib shown in cross-section.

FIGURE 5 is a fragmentary view of the panelboard mounting rib looking inthe direction of arrows 55 of FIGURE 4.

FIGURE 6 is a front elevation of the receptacle of FIGURE 4.

FIGURE 7 is a plan view of the receptacle of FIG- URE 6'.

FIGURE 8 is a plan view of one of the contacts connectable to the powersource.

FIGURES 8a and 8b are side elevations of the contact of FIGURE 8 lookingin the direction of the respective arrows 8a8b.

FIGURE 9 is an exploded perspective of the receptacle of FIGURES 4-6.

FIGURE 10 is an electrical schematic of the elements shown in FIGURE 2.

Now referring to the figures, plug cap or panel receptacles 11 and 12are shown in FIGURES 1-3 as being mounted on a panelboard of the typedescribed in detail in US. Patent 2,428,320. This panelboard includes aback plate 13 and a mounting rib 14 extending upwardly from plate 13 atright angles. Rib 14 is provided with a U-shaped cap 15 along the freeupper edge thereof. Rib 14 is also provided with two rows of guideapertures defining circuit breaker locations. That is, upper aperture16a and lower aperture 17a define a circuit breaker location for adevice such as receptacle 11 mounted to the right side of rib 14 withrespect to FIGURE 2 and upper aperture 16b together with lower aperture17bdefining a circuit breaker location for a device such as receptacle12 mounted to the left side of rib 14 with respect to FIGURE 2.

As will be hereinafter explained, receptacle 12 is adapted forconnection to a 240 volt circuit while receptacle 11 is adapted forconnection to a volt circuit. A typical arrangement of circuit breakersand receptacles is illustrated in FIGURE 2. The circuit breakers 18, 19are of the type described in detail in US. Patent 2,385,727. Theoperating handles 20, 21 of circuit breakers 18, 19, respectively, areconnected by screws 23 to tie bar 22 so that manual operation of circuitbreakers 18, 19 is simultaneous.

Jumpers 24, 25 connect one of the hot contacts of each receptacle 11 and12 to th load terminal 26 of circuit breaker 18 whose line terminal 27is connected to one of the hot wires of an energy source. The other hotcontact "ice of receptacle 12 is connected through jumper 28 to the loadterminal 29 of circuit breaker 19 whose line terminal 3b is connected tothe other hot wire of the energy source. Jumper Sll connects th otherterminal of receptacle lit to the panelboard neutral bar 32 which isconnected to the neutral line of the energy source. The energy source istypically a single phase three-Wire l20240 volt system wherebyreceptacle 12 provides twice the voltage as receptacle ll.

Receptacle 12 comprises a box-like housing 35 having a removable coverin the form of angle bracket E secured by screw 37' entered intothreaded aperture 38 of housing 35. Housing 35 is provided with threeopen sided chambers 39-41 within which contacts 42-44, respectively, aredisposed in alignment with prong receiving apertures 45-47,respectively, in the top surface of Blade-like grounding contact 4 ispart of contact ber 48 including hook 49 which is positioned externallyof housing 35 at the back thereof and locking car 539 lanced from blade44-. Connecting portion Ell joins blade 44 to hook 49. Hook 4-9 isreceived by mounting rib aperture 16a and as receptacle 12 is moveddownwardly hook d9 overlies a portion of mounting rib lld. Hook 49 isprovided with stamped teeth 52 which bite into rib 14 so as to provide agood equipment grounding connection therewith.

With a plug cap mounted to receptacle 12 the equipment grounding prong(FIGURE 4) 53 deflects contact blad 44 so that locking ear is projectedinto rib aperture 16a or at least a sufiicient distance toward aperture16a so that if an attempt is made to dismount receptacle 12 from rib 14at this time, cap is positioned in the path of locking ear 5h therebypreventing removal of receptacle 12.

Cover bracket 36 includes a leg portion 37 having a projection 38 nearthe end thereof. Projection 38 extends into rib apertur 17a to cooperatetherewith in aligning receptacle 12 in operative position upon rib 1d.

The other two contacts 42, 43 are of identical construction beingillustrated in detail in FIGURES 8-832. Contact 42 comprises threeblades 61-63 joined together by a U-shaped connecting portion 64. Blades61 and 62 are somewhat parallel, from portion 64, extend in the samedirection and are oriented so that their prong engaging surfaces faceone another. Blades er and 62 are positioned to receive therebetween oneof two aligned cap plug prongs (not shown) which will be receivedthrough prong-receiving apertures 45, 46.

The third blade 63 extends in the same direction as the other two blades61, 62 but is positioned in a plane generally perpendicular thereto.That is, the prong-engaging surface 63a of blade as faces the edges 61b,62b of blades 61, 62. Thus, blade 63 is positioned to be engaged by aparallel cap plug prong of the type which would be in serted throughprong-receiving apertures 65, d6 of receptacle 11.

Both arms of U-shaped connecting portion are provided with tappedapertures 67a, 67b. Aperture 57a receives binding post screw 63 whileaperture 67b receives binding post screw 69. Thus, it is seen thatbecause two tapped apertures 67a, 6% are provided, both of the contacts4-2, 43 which are connected to the hot wires of the power source may beidentical construction. Screws as, 69 are accessible through the opensides of chambers 39, 40.

Receptacles 11 and 12 are of identical construction except for thehousings thereof. That is, housing a of receptacle 11 is provided withparallel prong-receiving apertures, 65, 66 whereas housing 35 ofreceptacle 1?; is provided with aligned prong-receiving apertures .5,4d. The internal chambers and contacts therein of both housings 35 and3501 are identical.

The different orientation of the prong-receiving apertures provides aconvenient keying means. That is, plug caps connected to 120 voltequipment are supplied with parallel prongs and may be inserted intovolt receptacle 11 while these caps cannot be inserted into 240 voltreceptacle 12.

In the foregoing, I have described my invention only in connection withpreferred embodiments thereof. Many variations and modifications of theprinciples of my invention within the scope of the description hereinare obvious. Accordingly, I prefer to be bound not by the spechicdisclosure herein but only by the appended claims.

I claim:

1. A plug receptacle mountable on a panelboard at a circuit breakerlocation thereof, said receptacle comprising a housing having an openback and a cover therefor, a first and a second prong-receiving contactmounted within individual recesses of said housing and retained thereinby said cover, prong receiving apertures in the front thereof alignedwith said contacts, said housing also having holes in a side thereofthrough which said contacts are accessible for circuit connections; eachof said contacts comprising a pair of blades having opposed faces and athird blade extending in the direction of said pair of blades and whoseface is opposite the sides of said pair of blades whereby said contactsmay receive flat prongs oriented in a first position as well as at rightangles to said first position; a connecting formation electricallyconnecting said pair of prongs to said third prong, said formationhaving in opposed surfaces thereof tapped binding post screw receivingapertures; a grounding contact disposed within another recess of saidhousing and aligned opposite another prong-receiving aperture of saidhousing; a mounting hook extending from said grounding contact through afirst wall of said housing opposite said side of said housing.

2. A plug receptacle mountable on a panelboard at a circuit breakerlocation thereof, said receptacle comprising a housing having an openback and a cover therefor, a first and a second prong-receiving contactmounted within individual recesses of said housing and retained thereinby said cover, prong-receiving apertures in the front thereof alignedwith said contacts, said housing also having holes in a side thereofthrough which said contacts are accessible for circuit connections; eachof said contacts comprising a pair of blades having opposed faces and athird blade extending in the direction of said pair of blades and whoseface is opposite the sides of said pair of blades whereby said contactsmay receive fiat prongs oriented in a first position as well as at rightangles to said first position; a connecting formation electricallyconnecting said pair of prongs to said third prong, said formationhaving in opposed surfaces thereof tapped binding post screw receivingapertures; a grounding contact disposed within another recess of saidhousingand aligned opposite another prong-receiving aperture of saidhousing; a mounting hook extending from said grounding contact through afirst wall of said housing opposite said side of said housing; a lockingear projecting from said grounding contact, biased toward unlockingposition and movable to locking position through engagement of saidgrounding contact by a grounding prong of a plug; said car when inlocking position preventing dismounting of said receptacle.

3. A plug receptacle mountable on a panelboard at a circuit breakerlocation thereof, said receptacle comprising a housing having an openback and a cover therefor, a first and a second prong-receiving contactmounted within individual recesses of said housing and retained thereinby said cover, prong-receiving apertures in the front thereof alignedwith said contacts, said housing also having holes in a side thereofthrough which said contacts are accessible for circuit connections; eachof said contacts comprising a pair of blades having opposed faces and athird blade extending in the direction of said pair of blades and whoseface is opposite the sides of said pair of blades whereby said contactsmay receive fiat prongs oriented in a first position as .well as atright angles to said first position; a connecting formation electricallyconnecting said pair of prongs to said third prong, said formationhaving in opposed surfaces thereof tapped binding post screw-receivingapertures; a grounding contact disposed Within another recess of saidhousing and aligned opposite another prong-receiving aperture of saidhousing;

a mounting hook extending from said grounding contact through a firstwall of said housing opposite said side of said housing; a locking earprojecting from said grounding contact, biased toward unlocking positionand movable to locking position through engagement of said groundingcontact by a grounding prong of a plug; said car when in lockingposition preventing dismounting of said receptacle; said hook havingintegral teeth on the inner surface thereof. 7 e

4. A plug receptacle mountable on a panelboard at a circuit breakerlocation thereof, said receptacle comprising a housing having an openback and a cover therefor, a first and a second prong-receiving contactmounted within individual recesses of said housing and retained thereinby said cover, prong-receiving apertures in the front thereof alignedwith said contacts, said housing also having holes in a side thereofthrough which said contacts are accessible for circuit connections; agrounding contact disposed within another recess of said housing andaligned opposite another prong-receiving aperture of said housing; amounting hook extending from said grounding contact through a first wallof said housing opposite said side of said housing.

5. A plug receptacle mountable on a panelboard at a circuit breakerlocation thereof, said receptacle comprising a housing having an openback and a cover therefor, a first and a second prong-receiving contactmounted within individual recesses of said housing and retained thereinby said cover, prong-receiving apertures in the front thereof alignedwith said contacts, said housing also having holes in a side thereofthrough which said contacts are accessible for circuit connections; agrounding contact disposed within another recess of said housing andaligned opposite another prong-receiving aperture of said housing; amounting hook extending from said grounding contact through a first wallof said housing opposite said side of said housing; a locking earprojecting from said grounding contact, biased toward unlocking positionand movable to locking position through engagement of said groundingcontact by a grounding prong of a plug; said ear when in lockingposition preventing dismounting of said receptacle.

6. A plug receptacle mountable on a panelboard at a circuit breaker.location thereof, said receptacle comprising a housinghaving an openback and a cover therefor, a first and a second prong-receiving contactmounted within individual recesses of said housing and retained thereinby said cover, prong-receiving apertures in the front thereof alignedwith said contacts, said housing also having holes in a side thereofthrough which said contacts are accessible for circuit connections; agrounding contact disposed within another recess of said housing andaligned opposite another prong-receiving aperture of said housing; amounting hook extending from said grounding contact through a first wallof said housing opposite said last recited wall of said housing; saidhook having integral teeth on the inner surface thereof.

7. In combination a mounting rib extending perpendicular to the surfaceupon which it is mounted, said rib including a plurality of first meanseach defining a circuit breaker location, a plug receptacle mounted at afirst of said locations; said receptacle comprising a housing having anopen back and a cover therefor, a first and a second prong-receivingcontact mounted within individual recesses of said housing and retainedtherein by said cover, prong-receiving apertures in the front thereofaligned with said contacts, said housing also having holes in a sidethereof through which said contacts are accessible for circuitconnections; a mounting hook extending from said housing beyond a firstwall thereof in operative engagement with said mounting rib for securingsaid receptacle thereto; a grounding contact disposed within anotherrecess of said housing and aligned opposite another prong-receivingaperture, a locking ear projecting from saidhousing beyond said firstwall, means biasing said ear to unlocking position, said ear beingoperatively connected to said grounding contact whereby said ear ismoved to locking position through engagement of said grounding contactby a grounding contact of a plug.

8. In combination a mounting rib extending perpendicular on the surfaceupon which it is mounted, said rib including a plurality of first meanseach defining a circuit breaker' location, a plug receptacle mounted ata first of said locations; said receptacle comprising a housing havingan open back and a cover therefor, a first and a second prong-receivingcontact mounted within individual recesses of said housing and retainedtherein by said cover, prong-receiving apertures in the front thereofaligned with said contacts, said housing also having holes in a sidethereof through which said contacts are accessible for circuitconnections; a mounting hook extending from said housing beyond a firstwall thereof in operative engagement with said mounting rib for securingsaid receptacle thereto; a grounding contact disposed fwithin anotherrecess of said housing and aligned opposite another prong-receivingaperture, a locking ear projecting from said housing beyond said firstwall, means biasing said ear to unlocking position, said ear beingoperatively connected to said grounding contact whereby said ear ismoved to locking position through engagement of of said groundingcontact by a grounding contact of a plug; means carried by said riboperativcly positioned to cooperate with said car when in lockingposition to prevent dismounting of said receptacle from said rib.

9. In combination a mounting rib extending perpendicular to the surfaceupon which it is mounted, said rib including a plurality of first meanseach defining a circuit breaker location, a plug receptacle mounted at afirst of said locations; said receptacle comprising a housing having anopen back and a cover therefor, a first and a second prong-receivingcontact mounted within individual recesses of said housing and retainedtherein by said cover, prong-receiving apertures in the front thereofaligned with said 'contacts, said housing also having holes in a sidethereof through which said contacts are accessible for circuitconnections; a mounting hook extending from said housing beyond a firstwall thereof in operative engagement with said mounting rib for securingsaid receptacle thereto; a grounding contact disposed within anotherrecess of said housing and aligned opposite another prong-receivingaperture, a locking ear projecting from said housing beyond said firstwall, means biasing said ear to unlocking position, said car beingoperatively connected to said grounding contact whereby said ear ismoved to locking position through engagement of said grounding contactby a grounding contact of a plug; means carried by said rib operativclypositioned to cooperate with said ear when in locking position toprevent dismounting of said receptacle from said rib; a mounting bracketextending from said cover substantially parallel to said rib.

10; In combination a mounting rib extending perpendicular to the surfaceupon which it is mounted, said rib including a plurality of first meanseach defining a circuit breaker location, a plug receptacle comprising ahousing having an open back and a cover therefor, a first and a secondprong-receiving contact mounted within individual recesses of saidhousing and retained therein by said cover, prong-receiving apertures inthe front thereof aligned with said contacts, said housing also havingholes in a side thereof through which said contacts are accessible forcircuit connections; a mounting hook extending from said housing beyonda first Wall thereof in operative engagement with said mounting rib forsecuring said receptacle thereto; a grounding contact disposed withinanother recess of said housing and aligned opposite anotherprong-receiving aperture, a locking ear projecting from said housingbeyond said first wall, means biasing said ear to unlocking position,said ear being operatively connected to said grounding contact wherebysaid ear is moved to locking position through engagement of saidgrounding contact by a grounding contact of a plug; means carried bysaid rib operatively positioned to cooperate With said ear when inlocking position to prevent dismounting of said receptacle from saidrib; a mounting bracket extending from said cover substantially parallelto said rib, said mounting bracket having a formation cooperating withmeans carried by said rib to accurately position said receptacle at saidlocation.

References Cited in the file of this patent UNITED STATES PATENTSZiegler Sept. 29, Thomas Mar. 27, De Reamer Oct. 21, Swenson Feb. 21,Bentley May 30, Reeves Ian. 27, Dyer et a1. June 20, Windsor Jan. 21,Platz Sept. 30, Robertson et a1 Sept; 30, Cook Aug, 2, Grohsgal May 2,Parish et al. Nov. 18, Shenton Mar. 16, Hutt -.Aug. 10, Dupre Dec. 27,Herrmann et al Mar. 31, Platz Feb. 9,

4. A PLUG RECEPTACLE MOUNTABLE ON A PANELBOARD AT A CIRCUIT BREAKERLOCATION THEREOF, SAID RECEPTACLE COMPRISING A HOUSING HAVING AN OPENBACK AND A COVER THEREFOR, A FIRST AND A SECOND PRONG-RECEIVING CONTACTMOUNTED WITHIN INDIVIDUAL RECESSES OF SAID HOUSIG AND RETAINED THEREINBY SAID COVER, PRONG-RECEIVING APERTURES IN THE FRONT THEREOF ALIGNEDWITH SAID CONTACTS, SAID HOUSING ALSO HAVING HOLES IN A SIDE THEREOFTHROUGH WHICH SAID CONTACTS ARE ACCESSIBLE FOR CIRCUIT CONNECTIONS; AGROUNDING CONTACT DISPOSED WITHIN ANOTHER RECESS OF SAID HOUSING ANDALIGNED OPPOSITE ANOTHER PRONG-RECEIVING APERTURE OF SAID HOUSING;